Trichlorindigo and process of making same.



NIT D sira rnsrarnnr orricn.

-GADIENT ENGI AND HERMAN KRAFT, OF BASEL, SWITZERLAND, ASSIGNORS TO THE FIRM OF SOCIETY OF CHEMICAL INDUSTRY IN BASliE, OF BASEL, SWITZERLAND.

, TRIQHLORINDIGO AND PROCESS OF MAKING SAME.

- Patented Sept. 29, 1908.

To all whom it may concem: e

' Be it known that we, Gnotnn'r ENGI, doctor of hilosophyand chemist, a citizen of the Swiss Republic, and resident of Basel, Switzerland, and HERMAN Knar'r, doctor of philosophy and chemist, a subject of the Emperor of Austriad'lungary, and a resident of Basel, Switzerland, have invented a new and useful Trichloro Derivative of Indigo and a Process of Mal ing"San'1e,'of which the following is a full, clear, and exact specification.

Hltherto'nothing has been known relatively to trichloro derivatives of indigo. WVc have now found, that a trichlorindigo can be prepared by a direct chlorination of indigo,-Wheniindigo suspended in an aromatic liiitrohydrocarbon, as for, instance nitrobenacne, is treated with chlorin in presence of a suitableagent capable to transmit halogen, for instance the antimony chlorids. This result isthe more surprising as according to the indication of the German Patent 160817 the treatment of indigo suspended in anhydrous indifferent solvents, as for instance carbon'tetrachlorid, with chlorin in presence of. an agent capable to transmitchlormgives only chlorinated products of decomposition which lose their chlorin 'by their treatment or boiling with soda lye.

The new process is illustrated by the following example: 26.2 parts of indigo are sus-.

pended in 100 parts of nitrobenzene; to this suspension 10 parts antimony pentachlorid.

are added and hereafter 27 parts of chlorin are introduced in the mixture While stirring and cooling with ice. The chlorinated product is separated by filtration and suction, boiled with alcohol anddried. The violet powder of bronze luster thus obtained con- I sists principally of trichlorindigo. It dissolves in cold concentrated sulfuric acid with greenish blue coloration turning to pure blue on heating. It is hardly soluble in alcohol, and very (lifficultlysoluble in chloroform and benzene to a blue solution.

It dissolves sufficiently easily in nitrobcnzene to a reddish blue solution; by cooling down 'this solution the. dyeslutf "crystallizes in the form of small needles. By its treatment with an alkali and a hydrosulfite it yields a yellowish vat dyeing unmordanted cotton vivid blue tints fast to washing, light and chlorin.

\Vhat we claim is:

1. The herein described process for the manufacture of trichlorinated indigo, which consists in tl'ttlllllg indigo suspended in an aromatic nitroh'ydrocarbon with chlorin in presence of a suitable agent capable of transmitting a halogen. I

2. The herein described process for the manufacture of trlchlorlnated indigo, which consists in treating indigo suspended in ni- In witness whereof we have hereunto signed our names this fourth day of April 1-908, in the presence of two subscribing witnesses.

GADIENT ENGI. HERMAN KRAFT Witnesses:

AnNoLn ZUBnn, AMAND Rrr'run. 

